03 996TT:

305/30/18 rear, but what front is everyone using with the AWD cars? Thanks in advance.

Greg.

 

295-30-18 R
225-40-18 F

 

Yep. Your only rear choice is the P245/35ZR-18
for the front. The real choice for the rear is
285/30R18, to get the rolling diameters the
same. The 305 is a bit taller, which means
the fronts will be turning faster, which means
they may be driving against the viscous power
transfer unit, which means you might push, and
also heat that unit...
Joe

 

Hi, sorry, it was early, and I wasn't clear...

The two Hoosier sets options are:

P245/40ZR-18
P305/30ZR-18
these have circumferances:
79.6
80.4 (may cause push)

or

P245/35ZR-18
P285/30ZR-18
with circumferances
77.1
77.3 (very close to same-size)

 

The CORRECT two options to keep diameters in check are:

Front 245/35/18
Rear 285/30/18


OR - for more rear grip and less oversteer

245/40/18
305/30/18

Diameters will be in check. DO NOT USE 305 rears with 245/35 fronts. Too much delta in diameter and likely ABS/PSM lights.

 

Agreed, 245s up front. That's what we used when racing a 993TT. But it was 2WD converted ...

 

When I ran Hoosiers on my 996 TT I used 245/40/18 F and
305/30/18 R. If you go that route, just so you know, you might rub the fender liners on the rear. I and a number of friends wore holes in the rear fender liners--it's not the end of the world since it's plastic (albeit expensive plastic) that can be replaced.

I have since went with Michelin Pilot Sport Cups in the stock tire sizes. Not quite as much grip as Hoosiers nor are they as good as Hoosiers at cooler temps, but the Cups last a tad longer, and if you're of a mind to, you can drive to and from the track on the Cups.